I. Field
The present disclosure generally relates to audio and speech signal capturing. More specifically, the disclosure relates to mobile devices capable of initiating and/or terminating audio and speech signal capturing operations, or interchangeably logging operation, based on the analysis of audio context information.
II. Description of Related Art
Thanks to the power control technology advance in Application Specific Integrated Circuits (ASIC) and increased computational power of mobile processors such as Digital Signal Processor (DSP) or microprocessors, an increasing number of mobile devices are now capable of enabling much more complex features which were not regarded as feasible until recently due to the lack of required computational power or hardware (HW) support. For example, mobile stations (MS) or mobile phones were initially developed to enable voice or speech communication over traditional circuit-based wireless cellular networks. Thus, MS was originally designed to address fundamental voice applications like voice compression, acoustic echo cancellation (AEC), noise suppression (NS), and voice recording.
The process of implementing a voice compression algorithm is known as vocoding and the implementing apparatus is known as a vocoder or “speech coder.” Several standardized vocoding algorithms exist in support of the different digital communication systems which require speech communication. The 3rd Generation Partnership Project 2 (3GPP2) is an example standardization organization which specifies Code Division Multiple Access (CDMA) technology such as IS-95, CDMA2000 1x Radio Transmission Technology (1xRTT), and CDMA2000 Evolution-Data Optimized (EV-DO) communication systems. The 3rd Generation Partnership Project (3GPP) is another example standardization organization which specifies the Global System for Mobile Communications (GSM), Universal Mobile Telecommunications System (UMTS), High-Speed Downlink Packet Access (HSDPA), High-Speed Uplink Packet Access (HSUPA), High-Speed Packet Access Evolution (HSPA+), and Long Term Evolution (LTE). The Voice over Internet Protocol (VOIP) is an example protocol used in the communication systems defined in 3GPP and 3GPP2, as well as others. Examples of vocoders employed in such communication systems and protocols include International Telecommunications Union (ITU)-T G.729, Adaptive Multi-Rate (AMR) codec, and Enhanced Variable Rate Codec (EVRC) speech service options 3, 68, and 70.
Voice recording is an application to record human voice. Voice recording is often referred to as voice logging or voice memory interchangeably. Voice recording allows users to save some portion of a speech signal picked up by one or more microphones into a memory space. The saved voice recording can be played later in the same device or it can be transmitted to a different device through a voice communication system. Although voice recorders can record some music signals, the quality of recorded music is typically not superb because the voice recorder is optimized for speech characteristics uttered by a human vocal tract.
Audio recording or audio logging is sometimes used interchangeably with voice recording but it is sometimes understood as a different application to record any audible sound including human voice, instruments and music because of its ability to capture higher frequency signals than that generated by the human vocal tract. In the context of the present application, “audio logging” or “audio recording” terminology will be broadly used to refer to voice recording or audio recording.
Audio logging enables recording of all or some portions of an audio signal of interest which are typically picked up by one or more microphones in one or more mobile devices. Audio logging is sometimes referred to as audio recording or audio memo interchangeably.